Field of Invention
The present invention relates to communication field, and specifically to a method for allocating multi-UEs' Sounding Reference Signal (SRS) uplink resources, and an eNB for allocating multi-UEs' SRS uplink resources with the method.
Description of Prior Art
In an LTE (Long Term Evolution) system, Sounding Reference Signal (SRS) in an uplink channel is a signal sent to an eNB by a User Equipment (UE), which can be used for an eNB to sound and evaluate the quality of uplink channel. The eNB optimizes and adjusts the scheduling of uplink data according to the result of the sounding and evaluation, such as frequency resource occupied during uplink transmission, or the used modulation coding mode. In a TDD LTE mode, a UE can transmit a Sounding Reference Signal (SRS) in a normal uplink subframe or Uplink Pilot Time Slot (UpPTS) based on the configuration result sent from eNB. Herein, a criterion of configuring resource at UE can refer to relevant descriptions of 36.211 and 36.213 in 3GPP Provisions.
According to 3GPP, an E-UTRAN NodeB (eNB) can allocate the uplink resources of SRS for each UE in time and frequency domains by cell specific parameters in System Information Blocks (SIB) messages and by UE specific parameters in Radio Resource Control (RRC) messages. If there are multiple UEs in the cell, however, there is not a method for allocating uplink resources for each UE's SRS automatically both in time domain and frequency domain in the prior art.
CN Invention Patent Application (Publication No. CN 101330325A) involves allocating a resource for SRS of a terminal by a base station, wherein resource is allocated for one UE in frequency domain by an SRS bandwidth parameter (BSRS) and an SRS frequency range parameter (nRRC). This solution provides the method for allocating resource for one UE's SRS in frequency domain with an SRS bandwidth parameter (BSRS) and an SRS frequency range parameter (nRRC). However, this method just supports one UE's SRS resource allocation in frequency domain. It doesn't support resource allocation in both time and frequency domains automatically for multiple UEs' SRS.
CN Invention Patent Application (Publication No. CN 101335969A) involves a method for computing parameters of a resource for transmitting SRS in uplink pilot time slot (UpPTS) by a terminal. The SRS signal is transmitted on the resource. The index is determined by a frequency positions unit of random access channels, i.e., physical random access channel (PRACH) channels, when the PRACH channel contains a sub-carrier on a lower boundary of system bandwidth. The lower boundary of the system bandwidth is taken as the initial position of the maximal SRS bandwidth. This solution provides a method for allocating resources for one UE's SRS on frequency domain with initial position of the maximal SRS bandwidth. However, this method just supports one UE's SRS resources allocation in frequency domain. It doesn't support resource allocation in both time and frequency domains automatically for multiple UEs' SRS.
CN Invention Patent Application (Publication No. CN 101340383A) involves a method for determining resource block (RB) number of SRS bandwidth in frequency domain using the difference between the corresponding RB number of an uplink system bandwidth in the frequency domain and the maximum RB number occupied by a physical uplink control channel (PUCCH) in a time slot determined according to current system parameter. Therein the corresponding RB number of SRS-bandwidth is an even number, and corresponding prime factor of the corresponding RB number of SRS-bandwidth in the frequency domain comprises 2, 3 and 5. This solution provides the method for determining resource block (RB) number of SRS bandwidth in frequency domain. However, this method just supports SRS resource allocation in frequency domain with different resource blocks. It doesn't support resource allocation in both time and frequency domains automatically for multiple UEs' SRS.
US Utility Patent Application (Publication No. US 2009/0034468A1) involves a method for associating a sounding period to each sounding resource, and time-sharing the sounding resource across a set of UEs for different sub-frames. Therein the UEs require different sounding periods that are periodic and non-changing in time and allocating the time-sharing UEs to sub-frames in differing periods. A sounding resource sharing tree is formed recursively. A vertex of the sounding resource sharing tree is selected and the sounding resources are allocated based on the selected vertex. This solution provides the method for allocating sounding resource on time domain with different sounding periods. However, this method just supports SRS resource allocation on time domain with different period, but doesn't support resource allocation in both time and frequency domains automatically for multiple UEs' SRS.
PCT International Patent Application (Publication No. WO 2009/019062 A2) involves a method for determining different sets of configuration parameters for the sounding signal transmissions for a mobile terminal. The determined different sets of configuration parameters are transmitted to the mobile terminal, for enabling the mobile terminal to generate different sounding signals for different users such as channel-quality and timing estimations by the wireless communication network. This solution provides the method for allocating sounding signal resources for one mobile terminal with different configuration parameters sets. This method just supports one UE's SRS resource allocation with different sets of configuration parameters. It doesn't support resource allocation in both time and frequency domains automatically for multiple UEs' SRS.
CN Invention Patent Application (Publication No. CN 101404817A) involves a method for allocating bandwidth of SRS with respect to a user terminal of a particular cell, according to an allocation policy. The policy is defined with a principle that the usage amount of bandwidth is minimized when bandwidth allocation is changed. An instruction containing the bandwidth information is transmitted to the UE, before and after changing the bandwidth. This solution provides the method for allocating bandwidth of SRS for a UE. However, this method just supports one UE's SRS resource allocation in frequency domain with different bandwidth. It doesn't support SRS resource allocation in both time and frequency domains automatically for multiple UEs' SRS.
CN Invention Patent Application (Publication No. CN 101404794A) involves a method for determining the sub-frame offset for transmission of an SRS based on its transmission period, corresponding to the symbols used for transmitting the SRS in an uplink pilot time slot of a common uplink sub-frame. This solution provides the method to determine the sub-frame offset for SRS transmission on time domain. However, this method just supports SRS resource allocation in time domain with different sub-frame offset based on its transmission period. It doesn't support SRS resource allocation in both time and frequency domains automatically for multiple UEs' SRS.
As can be seen from the above, the existing solutions can just allocate SRS resources for single UE or just allocate SRS resources either in time domain or in frequency domain. They cannot allocate SRS resources for multiple UEs automatically both in time domain and frequency domain.